1. Field of the Invention
The invention relates to a fuel supply device for an internal combustion engine.
2. Description of Related Art
Japanese Patent Application Publication No. 2012-237274 (JP 2012-237274 A) discloses a fuel supply device for an internal combustion engine in which a low-pressure fuel pipe that receives fuel supply from a feed pump is connected to a first fuel injection valve and a high-pressure fuel pipe that branches from the low-pressure fuel pipe is connected to a second fuel injection valve. In addition, a high-pressure pump that boosts the fuel in the high-pressure fuel pipe and supplies the fuel to the second fuel injection valve is disposed in the device.
In the fuel supply device described above, the low-pressure fuel pipe is connected to the high-pressure pump via the high-pressure fuel pipe. Accordingly, when the fuel pressure in the high-pressure fuel pipe changes as a result of the driving of the high-pressure pump, the changing fuel pressure propagates as pulsation to the fuel in the low-pressure fuel pipe. This causes the pulsation of the fuel pressure in the low-pressure fuel pipe to increase.
An error from a proper value occurs in the fuel injection amount of the first fuel injection valve when the pulsation of the fuel pressure in the low-pressure fuel pipe increases. This is because the fuel injection amount of the first fuel injection valve is determined by the valve opening time of the fuel injection valve and the pressure of the fuel supplied to the fuel injection valve (fuel pressure in the low-pressure fuel pipe). The error of the fuel injection amount of the first fuel injection valve described above may affect the operation of the internal combustion engine.